Melting glow plug coils!
 

Today I was at the track running the engine rich at stock needle settings - 4.5 turns out - HSN, 3 turns out - LSN, Flush with carb body - MSN. Usually I do this for a few mintues to reset everything and flush out any dirt. Well after about four laps (smoke at full throttle, raw fuel spitting out at idle) I shut her down. After about 30 seconds I attempted restart the engine with no luck. Upon inspection the glow plug coil had melted - brand new! Then it did it again within three laps on another brand new plug!

After I burned two plugs out and none left, I packed up my things.

I have a Nova TN12 (based off RS12), Byrons Race 3000 (30%), and O.S. #8 plugs, 90-95 degrees out, engine is totally stock (no shims added). At the end of the last race I noticed the car was having problems.

Is it possible that the car is too rich? This isn't making any sense to me. Thanks in advance.

Should I be using a colder plug?

Hmmmmm, the same problem I had before.
Does your engine vibrate too much? Does the button head in the combustion chamber a little rough?
Check the piston, bearings, and excessive play on the connecting rod brass bushings.
Replace them if necessary. Or try to add 0.1mm shims to minimize detonation.

I'm almost positive it is the 30% nitro and the OS #8 that do not match. Can anyone confirm this?

Just one question... why use an OS #8 plug? Just use the Nova or RB ones... less fuzz and problems. Is normal or Turbo?

Normal/Standard. I'll be honest I am very disappointed with these. My Novas never gave me problems other than one. Where can I get them in the states?

Just use a Nova 7Cold or RB #7. Pay attention to the Combustion chamber height. If you find some Sirio #7 they work really fine too (Yep... are available on standard 1/4 UNF thread size - Are the buggy ones).

Can someone breakdown the RB Concepts plug number and heat ranges, thanks.

I would try to use a shorter plug. OS #8 is a standard plug as your said.

You probably save couple bucks using OS #8, but it is just better to use NovaRossi plug....

i blew every OS standard pug i ever had (A3 ,#8) (when i used a OS12TR) i found that they werent that good, i always ran the engine rich and i wasnt the only one having probs with them, i ended up selling the engine cheap and the other guy started using the R5 plug on 15% nitro

os plug
 

The os plugs are shorter than novarossi and the #8 is too hot for 30 percent fuel.

Can anyone break down the RB heat ranges/plug codes?

Yeah, I went through $20 worth of plugs. You live and learn I guess. :(

What's the difference between long and short plugs?

Check your engine's spec. the shim that come with stock engine has a limitation. most engines are good up to 25% nitro without adding a 0.1mm shim. (0.1=5% nitro) 30% nitro creates lots of compression. your problem is shimming.
i am almost sure that once you find out the max nitro for the stock setting and adding the right shimms your problem will go away.